Cómo obtener la primera clave en un objeto n en JavaScript
var obj = { "a" : 1, "b" : 2, "c" : 3};
alert(Object.keys(obj)[0]);
// alerts "a"
let objLength = Object.keys(obj).length
console.log(objLength)
// Logs 3 as "obj" has 3 keys
var objValue = Object.values(obj)[0]
console.log(objValue)
// Logs "1" as the value of the first key(a) is "1"
Fierce Ferret